Not only has he offended Muslims, Mexicans, women, the pope, his president, peaceful protesters at his increasingly fascist-style rallies, the residents of Brussels and reasonable opinion in general, he’s gone and ruined one of my favourite TV shows.

I’ve followed House of Cards since its launch, relishing the outrageous antics of Frank Underwood as he rose from amoral congressman to deeply evil president. Sometimes the script went over the top, as TV drama tends to, but somehow the suspension of disbelief was maintained.

Yes, it was an exaggerated depiction of power politics at its most brutal, and grew more so with each season. But in the era of Obama we could say that at least the reality was a lot more palatable, and enjoy House of Cards for what it was – escapist fiction with an A-list cast and an irreverent dose of political satire.

Now, the Netflix original feels too close to reality for comfort, and Kevin Spacey’s monstrous creation like a cautionary tale. Trump hasn’t committed murder, that’s true – although he has incited violence on the part of his supporters, and hinted darkly at “riots” if he is deprived of the GOP nomination, so there’s time yet. But the wilder excesses of his campaign would make Frank Underwood blush.

His attack on Ted Cruz’s spouse – albeit a response to publication of a “glamour shot” of the current Trump trophy wife – is the kind of thing Frank Underwood might well have dreamt up in one of his battles against his spouse Claire, or rival Heather Dunbar. It was dirty fighting, and confirmatory of all the stereotypes his critics associate with the Donald.

To campaign on the tweeted slogan “I’ll spill the beans on your wife” makes Trump look like the ultimate bogan, an uncivil boor who knows nothing about government and political leadership, but all about lawyers and litigation and how to engage the angry, paranoid, largely white electorate who appear to form the core of his support.

It is a new kind of celebrity culture, complete with Trump’s referencing of the National Enquirer as a publication to be trusted when following the campaign.

And much more gripping than the Kardashians or any of their ilk because, were the (still, just about) unthinkable to happen and Trump won not only the Republican primaries but the general election in November, the world would become an immeasurably scarier place than it already is. Trump would go from being a figure of fun around the globe to being the most powerful man on earth. This stuff matters.

A recent article by L. Gordon Crovitz for the Wall Street Journal analysed the Trump phenomenon through the prism of Daniel Boorstin’s influential 1961 concept of the pseudo-event. Boorstin, argued Crovitz, in his book The Image (which I highly recommend for its continuing relevance to our mediated politics), identified the rise of celebrity as a key criteria of fame and power in itself.

Even in the early 1960s, when JFK was in the White House, how someone came over in the media was coming to be regarded as more important than what they did in office.

Trump, by this logic, represents the ultimate triumph of the image, the name, the media persona over hard-won knowledge and political wisdom. We know him from The Apprentice, from his many wives and business ventures, many of them failures, from his pursuit of famous women like Princess Diana and English journalist Selina Scott. He’s famous on TV, and he speaks his mind, and that’s enough to become president in 2016.

I’m not sure if I agree with this fatalism, though. Trump has sought political power before, including his promotion of the absurd “birther” movement – a lobby group consisting of barely disguised racists who sought to prove that Barack Obama was not born in the US and was not therefore eligible to be its president. He failed then, and should have failed this time too, like Sarah Palin did in 2008.

I have the suspicion that he entered the race never expecting to win, but as a promotional strategy for his corporate interests. To his alarm as much as ours, one might speculate, he has so far been unable to scare people off.

So what changed?

One explanation is unavoidable – the Republican Party is so starved of credible presidential candidates that Trump was able to shine despite himself. Carson, Rubio, Fiorina and the rest, for all their self-regard, could not convince GOP primary voters to favour them over a man who struggles to craft a coherent sentence, let alone a visionary foreign policy or global leadership strategy worthy of the presidency.

A bit like Jeremy Corbyn in the UK, party rules combined with hopelessly weak alternative candidates allowed a marginal outsider to walk in and steal the party from under itself.

Let me say at this point that we Scots have to take our share of the blame for this hugely entertaining mess. Not only is his mother Scottish, but the Labour government of my own dear homeland, greedy for the inward investment dollar, deemed it appropriate to name Donald Trump as the country’s GlobalScot business ambassador in 2006.

The Scottish National Party endorsed that approach, kissing Trump’s arse for years as he built an exclusive golf course and hotel for the wealthy in pristine Scottish countryside.

That all went pear-shaped when Trump and the Scottish government fell out over the former’s [opposition to offshore wind farms, which he claimed would spoil his rich clients’ sea views, though his “ambassadorial” status was not removed until December 2015 when Trump called for the banning of all Muslims from the US.

I apologise, friends, from the bottom of my heart, for my compatriots’ role in making Trump the monster he has become.

And Australia, don’t forget, has had its Pauline Hanson, and is still embarrassed by its brief flirtation with Clive Palmer as a serious politician. Populists can arise and get a hearing in any democracy, which is both a strength and a weakness of our system. The danger comes when there is a political vacuum into which such figures can pour their bile, and captivate that segment of the citizenry which mistakes dangerous demagoguery for “telling it like it is”.

One doesn’t have to be a Democrat to hope that the Trump juggernaut will come to a halt when the general election campaign properly starts. Even many of the GOP elders in Washington, D.C. – Trump’s hated “elites” – seem ready to endorse Hillary Clinton rather than this crude party gatecrasher in their well-heeled corridors of power.

Until that moment comes, the world watches events in the US with dropped jaws and wide-open mouths. And it might never come. The US is in uncharted electoral territory, and no-one can predict with certainty where the journey ends.

Trump is immensely newsworthy and media-friendly, and his primary success makes him even more so with each winning result. Now he has momentum, and credibility. The GOP voters have spoken, have they not?

This might look to the rest of us like US celebrity culture on a really bad acid trip, but it’s also democracy at its finest.